Interoperation between a subsequent evolution network of the code division multiple access (CDMA for short) network and the long term evolution (LTE for short) network is a trend of network development. However, evolution from the commercial CDMA network to the LTE network will be a complicated replacement process. Moreover, in this replacement process, there will be a very long coexistence period, during which these two wireless networks will be interconnected and intercommunicated.
Currently, the 3GPP2 related work group has formulated the LTE-High Rate Packet Data (HRPD) interoperation specification C.S0087 for supporting interconnection and intercommunication of the two networks described above. According to requirements proposed by operators at different stages, the formulation of this interoperation specification also experiences two stages. Achievement in the first stage is Version C.S0087-0_v1.0, which mainly supports idle to activation switching of an access terminal from a LTE system to a HRPD RevA system, and achievement in the second stage is Version C.S0087-0_v2.0, which adds support to reselection of the access terminal in an idle state from the HRPD system to the LTE system on the basis of the first version. In addition, the second version not only supports interoperation between the LTE and HRPD RevA systems, but also supports an interoperation function between the LTE and HRPD RevB systems.
In the C.S0087 specification, in order to ensure that the terminal has the ability to attach to a core network having interoperation ability, the air interface application layer protocol is required to be capable of supporting multiple packet data network (PDN) operation, i.e. the terminal should identify its support to ProtocolID 0x07 in high layer protocol attributes that it supports. The definition of ProtocolID 0x07 is contained in additional CDMA spread spectrum system management parameter protocol C.R1001 (see Version G).
When Version 1.0 of the C.S0087 specification is formulated, it is believed that interoperation requirements are mainly for real-time multimedia services. Therefore, only an enhanced multi-flow packet application bound to a service network subtype (enhanced multi-flow packet application subtype, i.e. EMPA, for short hereinafter, and its corresponding subtype value is 0x0009) is enhanced. When the terminal negotiates the ATSupportedFlowProtocolParametersPP attribute with a base station, the terminal is required to identify its support to ProtocolID 0x07 in this attribute.
Both an ordinary HRPD terminal capable of supporting the enhanced multi-flow packet application subtype and a HRPD terminal capable of supporting interoperation (eHRPD terminal for short) will contain the enhanced multi-flow packet application subtype into the ATSupportedApplicationSubtypes attribute at the beginning of session negotiation. In order to ensure that the base station can distinguish between the two terminals having different abilities described above, the C.R1001 specification defines a new alternate enhanced multi-flow packet application for eHRPD subtype (alternate enhanced multi-flow packet application subtype for short hereinafter, and its corresponding subtype value is 0xFFFE). When the terminal can report the alternate enhanced multi-flow packet application subtype in addition to the enhanced multi-flow packet application subtype, it is indicated that the enhanced multi-flow packet application subtype supported by the terminal can support an interoperation function, i.e. multi-PDN operation.
When version 2.0 of the C.S0087 specification is formatted subsequently, in order to support the HRPD RevB Version and further improve support to the HRPD RevA Version, a multi-flow packet application bound to a service network subtype (multi-flow packet application subtype, i.e. MPA, for short hereinafter, and its corresponding subtype value is 0x0005) and a multi-link multi-flow packet application bound to a service network subtype (multi-link multi-flow packet application subtype, i.e. MLMPA, for short hereinafter, and its corresponding subtype value is 0x000D) are enhanced as well. That is, for the MPA, when the terminal negotiates the SupportedHigherProtocolParameters attribute with the base station, the terminal is required to identify its support to ProtocolID 0x07 in this attribute, and for MLMPA, when the terminal negotiates the SupportedFlowProtocolParametersPP attribute with the base station, the terminal is required to identify its support to ProtocolID 0x07 in this attribute.
Similarly, in order to ensure the base station has an ability to distinguish the ordinary HRPD terminal capable of supporting the enhanced multi-flow packet application subtype from the eHRPD terminal capable of supporting interoperation, the C.R1001 specification is required to define a new eHRPD support null packet application subtype (null packet application subtype for short hereinafter, and its corresponding subtype value is 0xFFFE). When the terminal negotiates the ATSupportedApplicationSubtypes attribute with the base station, this application subtype should be contained, mainly indicating that the terminal supported multi-flow packet application subtype, enhanced multi-flow packet application subtype, and multi-link multi-flow packet application subtype all support the interoperation function, i.e. multi-PDN operation.
By analysis of protocol version evolution, it can be seen clearly that the value of the null packet application subtype introduced into Version C.S0087-0_v2.0 reuses the value of the alternate enhanced multi-flow packet application subtype introduced into Version C.S0087-0_v1.0. The present invention found that the above embodiments may introduce compatibility problem. For example, when a terminal supporting Version C.S0087-0_v1.0 access to a base station supporting Version C.S0087-0_v2.0, if the terminal carries an application subtype with the value being 0xFFFE when negotiating the ATSupportedApplicationSubtypes attribute, it is possible that the base station wrongly understands that the terminal supported multi-flow packet application subtype, enhanced multi-flow packet application subtype, and multi-link multi-flow packet application subtype can all support the interoperation function. Furthermore, it is possible that the base station selects to bind other application subtypes except the enhanced multi-flow packet application subtype to service flows for subsequent operation. The base station originally expects this application subtype to be able to meet support to multi-PDN, however, the terminal does not have such an ability actually. If the base station can know that the terminal only provides the interoperation function to the enhanced multi-flow packet application subtype, then the base station can select to bind correctly the enhanced multi-flow packet application subtype to the service flows for subsequent operation.